Swing stage scaffold



Dec. 15, 1953 R. ALLENBAUG SWING STAGE SCAFFOLD 2 Sheets-Sheet 1 FiledJune 13, 1952 Dec. 15, 1953 R. ALLENBAUGH SWING STAGE SCAFFOLD 2Sheets-Sheet 2 Filed June 15, 1952 Patented Dec. 15, 1953 swme STAGESCAFFOLD Ralph Allenbaugh, Mansfield, Ohio, assignor of one-half toWilberd F. Feigenbaum, Mansfield,

Ohio

Application June 13, 1952, Serial No. 293,322

20 Claims. (01; 254-176) This invention relates generally to swing stagescaffolds such as are used to support workmen and materials adjacent theexterior of a building or Wall while painting or otherwise workingthereon. More specifically the invention relates to a power-operatedmechanism by which a scaffold is raised and lowered as desired. Thisinvention is a modification of the scaffold hoisting mechanisms shown inmy co-pending application serial No. 102,488, filed July 1, 1949, andSerial No. filed November 6, 1950.

As shown herein, my improved swing stage scaffold comprises a pair ofspaced similar stirrups and a swing stage plank which extends betweenand is carried by the stirrups. The stirrups are adjustably secured forup and down movement to two spaced single strands of cable which aresecured to and extend downwardly from suitable supports which aremounted upon and extend outwardly from the top of a building or wall.Each stirrup has mounted thereon an electric motor operated mechanismwhich engages the associated strand of cable and is cnerativetomove thestirrup up and do n the cable and to hold the stirrup in any desiredposition.- The two mechanisms are identical and their construction issuch that they in effect climb up and down the suspended cables whenoperated, and remain in fixed position on the cable when not operating.They operate independently of each other, and are power-operated in bothdirections so that the scaffold cannot be lowered by gravity. In case ofa power failure while the scaffold is elevated the motors can be removedand manually operable cranks substituted therefor. means, which must bemanually released while descending, is provided to prevent falling ofthe scaffold in the event the motor-operated mechanism is damaged tosuch an extent that itwill not remain in fixed position on the cable.

The principal object of the invention is to provide an improved swingstag scaffold which is constructed to be adjustably supported for up anddown movement by two spaced single strands of rope or cable.

Another object of the invention isto provide a power-operated scaffoldhoisting mechanism of light weight which is very efficient in operation,is of simple construction and is relatively inexpensive to manufacture.I

Other and more limited objects of the invention will be apparent fromthe following specification and the accompanying drawings forming a partthereof wherein: p v I Fig. 1 is an end elevation of a swing stagescatfold constructed according to myinventiong- Safety braking Fig. 2 isa front elevation of the lefthand end thereof;

Fig. 3 is a horizontal section taken substantially on the line 3-3 ofFig. 1;

Fig. 4 is a vertical section taken on the line 44 of Fig. 3;

Fig. 5 is an enlarged detail section through the safety braking meanstaken on the line 55 of Fig. 1;

Fig. 6 is a horizontal section taken on the line 6-6 of Fig. 5;

Fig. 7 is a view similar to Fig. 5 taken on the line '!-1 of Fig. 1; andI Fig. 8 is a horizontal section taken on the line 8-8 of Fig. 7.

Referring to the drawings by reference characters the numeral lindicates a swing stage plank which is carried by two spaced similarstirrups 2. The stirrups 2 are mounted for up and down movement upon apair of cables 3 which are secured to'and hang down from a pair of fixedsupporting members which extend outwardly from the top of a building orwall. Each stirrup 2 has permanently mounted thereon a hoistingmechanism which is generally indicated by the numeral 6 and is driven byany suitable electric power means 1. The hoisting mechanisms 6 areoperative to move the stirrups 2 and the plank carried thereby up anddown the cables 3 and to hold the stirrups 2 in fixed position on thcables 3 as desired. i

' With the exception that one is lefthand and the other right hand thestirrups 2 and the hoisting mechanisms 6 carried thereby are identicalinconstruction and operation. Consequently. only thejleft hand stirrup andhoisting mechanism are shown and described herein.

The stirrup 2 comprises a horizontally disposed cylindrical bar 10having the upturned ends i which are permanently secured as by weldingin the lower ends of upwardly extending tubular side rods l2. Thetubular side rods [2 are disposed -in the same plane and extendvertically upwardly a short distance from the upturned ends l I of thebar In and then converge inwardly into engagement with opposite sides ofa vertically slotted guide sleeve l3 to which the upper ends of the rodsH are welded. The guide sleeve I3 is offset outwardly from the plane ofthe side rods H! a short distance so that a cable extending verticallydownwardly from the sleeve I 3 will be spaced from the stirrup 2. Twospaced horizontal tubular braces l4 and 15 extend between the rods l2and are welded thereto. A tube It is rotatably mounted upon the bar Hibetween collars 11 which are welded to the bar I0, one

adjacent each end thereof. A pair of spaced parallel upwardly extendingbolts |8 are rigidly secured to the tube I6, one adjacent each endthereof. The plank I is seated on the tube l6 and is clamped firmlythereto by a clamping bar H], which is slidably mounted upon the boltsl8, and a pair of wing nuts 20 threaded onto the bolts III. This meansof clam ing the plank to the stirrups 2 makes it possible to rais onestirru higher than the other without danger of the plank sliding out ofthe stirrups. A bracket 2| in which a back bar or guard rail 22 ismounted is welded to and extends forwardly from one of the upwardlyextending rods l2 near the upper end thereof. Pins 23 which are insertedthrough apertures in the back bar 22 prevent the back bar from slidingout of the brackets 2|.

The hoisting mechanism 5 comprises a gear case 25 which is rigidlysecured to the cross braces I4 and I5 by suitable clamping means 26. Ahorizontal shaft 21 which is perpendicular to the plane of the stirrup 2is rotatably mounted upon anti-friction bearing 28 carried by the case25. A worm gear 29 which is keyed to the shaft 21 within the case 25between the bearings 28 meshes with a worm 30 mounted upon a verticaldrive shaft 3| which is rotatably supported by anti-friction bearing 32carried by the case 25. The shaft 3| extends out through the top of thecase 25 and terminates in a triangular section 33. The shaft 3| isdriven in either direction by the electric power means 1 which isdetachably connected to the triangular end 33 of the shaft 3|.

As shown herein the electric power means '1 consists of a standardelectric drill which is available on the open market. It comprises areversible motor 35 having the hand grips 36, 31 and 38 secured thereto.Speed reduction gearing 39 is mounted in a casing 40 secured to thelower end of the motor 35. The motor 35 drives, through the reductiongearing 33, a chuck 4| by which the power means 1 as a whole isconnected to the end 33 of the shaft 3|. The power means 'I is removablysecured in place with the chuck 4| gripping the end 33 of the shaft 3|by a clamp 42 which secures the free end of the hand grip 31 to one ofthe uprights I2 and a screw 43 which secures the hand grip 35 to abracket 44 carried by the other upright I2. The operation of the motor35 is controlled by a switch which is actuated by a trigger 45 in thehand grip 35. The direction of rotation of the motor 35 is controlled bya reversing switch which is actuated by finger lever 46. Current issupplied to the motor 35 from any suitable source through a longextension cord 41.

A drum 50 and a traction pulley 5| are keyed to the projecting end ofthe shaft 21 with the drum 50 adjacent the housin 2 T e drum 5 has endflanges 52 Which are spaced far enough apart for the cable 3 to be woundaround the drum 50, between the end flanges, a plurality of turns. Thepulley abuts the outer end of the drum 50 and has a single peripheralgroove 53 the base of which is the same diameter as the diameter of thedrum 50, between the end flanges 52, so that the base of the groove 53and the outer surface of the drum 50 will have the same peripheral speedwhen rotated in unison by the shaft 21. As shown herein the drum 50 andtraction pulley 5| are made as separate units, but if desired thetraction pulley can be formed integrally with the drum 50. The drum 50is disposed a short distance outwardly from the stirrun 2, and the gearcase 25 and power mechanism '1 are disposed inwardly of the stirrup 2 asclearly shown in Figs. 2 and 3.

A bell crank lever 54 having the angularly disposed arms 55 and 56 ispivotally mounted on a stud 51 carried by a bracket 58 which is rigidlysecured to the cross brace IS in spaced relation rea-rwardly of the drumand traction pulley 5|. The arm extends upwardly and rearwardly from thepivot stud 51 and the arm 56 extends upwardly and forwardly from theupper end of the arm 55. A grooved idler pulley 60 is rotatably mountedupon a pivot stud 6| carried by the bell crank lever 54 near thejunction of the arms 55 and 56. A thin pressure wheel 62 is rotatablymounted upon a pivot stud 63 which is carried by the bell crank 54 atthe free end of the arm 55, The idler pulley 50 is disposed rearwardlyof the drum 50 and the pressure wheel 62 is disposed directly rearwardlyof the traction pulley 5| so that it extends into the groove 53 in thetraction pulley 5| during operation.

In use the cable 3 extends down through the slot 65 in the guide sleeveI3 and around the drum 50 a plurality of turns. From the top of the drum5|! the cable extends to the top of the idler pulley 6|! andsubstantially half way therearound. From the bottom of the idler pulley60 the cable 3 extends to the bottom of the traction pulley 5| and thensubstantially three quarters of the way around the traction pulley. Fromthe traction pulley 5| the cable 3 hangs loosely downwardly from betweenthe pulley 5| and the pressure wheel 62. After leaving the tractionpulley 5| the cable 3 extends through a slotted guide sleeve 63, similarto the sleeve l3, which is secured to and outwardly of the cross beam l5by arms 64. When the motor 35 is running the drum 56 and traction pulley5| will be rotated in unison through the reduction gearing 39, worm 30,worm gear 23 and shaft 2I. When the motor 35 is running in one directionthe cable 3 is wound onto the drum 50 at the end thereof adjacent thestirrup 2 and is withdrawn from the other end thereof and around theidler pulley 50 by the traction pulley 5|. Since the diameter of thedrum 50 and the diameter of the base of the trac tion pulley groove 53are the same the cable is withdrawn from the drum 5:) at the same linearspeed that it is wound onto the drum. When the motor 35 is running inthe opposite direction the cable 3 is fed around the idler pulley 60 andonto the outer end of the drum 50 by the traction pulley 5|. From thisit will be apparent that when the drum 50 and traction pulley 5| arebeing rotated counterclockwise as viewcd in Fig. l the stirrup 2 willclimb up the cable 3, and when rotated clockwise the stirrup willdescend the cable 3. The construction of the worm 30 and worm gear 29with which the worm meshes is such that they will lock the shaft 2'!against rotation when the motor 35 is not running.

During use the cable 3 must be maintained taut upon the drum 50 andtraction pulley 5| at all times so that there will be no slippagebetween the cable and the drum 50 and/or the pulley 5|. The pull on thelower stretch of the cable 3, after it leaves the drum 50, necessary tomaintain it taut upon the drum is very slight being at the most two orthree pounds. The idler pulley 60 and the pressure wheel 62 mounted uponthe bell crank 54 are provided for this purpose. The pressure wheel 52holds the cable 3 tight against the traction pulley 5| and the idlerpulley 60 guides the cable 3 from the drum 5' onto the traction pulleyThe idler pulley 60 and the cable 3 passing therearound cooperate torock the bell crank 54 towards the drum 5!! and thereby urge thepressure wheel 62 toward the traction pulley 5i so as to firmly grip thecable between the pressure wheel 62 and pulley 5!. Obviously the greaterthe weight suspended by the upper stretch of the cable, the tighter thecable will be gripped between the pressure wheel and traction pulley.

In order to retain the cable 3 in the slots t5 and B6 of the guidesleeves l3 and 63 and to provide braking means which will preventdropping of the stirrup 2 in the event the hoisting mechanism 6 becomesdisabled I provide a brake t! which is carried by the guide sleeve 53and a similar brake 53 which is carried by the guide sleeve 63. Thebrake 5! comprises a disc to which is eccentrically mounted upon aremovable pin "ii! carried by a pa? of ears H secured to and extendingoutwardly from the sleeve it one on each side of the slot 55. The disc69 has an actuating arm 12 formed integrally therewith and extendingoutwardly therefrom. The brake 63 comprises a disc 53, similar to thedisc 69, which is eccentrically mounted upon a removable pin M carriedby a pair of ears '55 which are secured to and extend outwardly from thesleeve 33 one on each side of the slot The disc 53 has an actuating armit formed integrally therewith and extending outwardly therefrom substantially parallel to the arm '52. The arms '52 and "F6 are tiedtogether by a link H which is pivotally secured to the outer ends of thearms. A handle 13, by which the link ll is raised to release the brakesSi and 58 in unison, is secured to the link Ti and extends inwardlytherefrom into position to be readily grasped by an operator. Thearrangement is such that the weight of the arms 12 and E6, the link lland the handle is always bias the brakes 6i and 68 into lockingengagement with the cable In descending the brakes 6i and 83 must bemanually held in re leased position by the handle '58 and link Tl.

While both of the brakes i5? and (i3 cooperate -31 to hold the stirrup 2in fixed position upon the cable 3, the primary purpose of the lowerbrake 68 is to prevent fouling of the cable 3 upon the drum 5% andpulleys 5i and so. In descending the traction pulley 5! in effect raisesthe lower stretch of the cable 3 and feeds it onto the drum 59, butsince the stirrup 2 and. the hoisting mechanism carried thereby aremoving downwardly at the same rate that the traction pulley iii istending to lift the lower stretch of the cable 3 there is no upwardmovement of the lower stretch of cable. But if only the upper brake 5?were provided the operator might forget to release the upper brake whenattempting to descend in which case the upper brake ti would hold thestirrup stationary and then the traction pulley would actually lift thelower stretch of the cable and foul it around the drum and pulley.

If desired the operating mechanism may be enclosed by a suitableremovable cover which will prevent workmen from getting their hands orclothing caught therein. Such a cover will also prevent damage to themechanism by falling articles.

From the foregoing it will be apparent to those skilled in this art thatI have provided a very simple and efficient mechanism for accomplishingthe objects of the invention.

t is to be understood that I am not limited to the specific constructionshown and described 6. herein as various modifications may be madetherein Within the scope of the appended claims,

What is claimed is:

1. A swing stage scaffold comprising a suspended cable, a stirrupadapted to support a plank, a guide sleeve through which said cablepasses carried by said stirrup at the upper end thereof, a gear casecarried by said stirrup below said guide sleeve, a shaft rotatablymounted in said gear case with one end thereof extending out from saidgear case, power means by which said shaft is rotated in eitherdirection carried by said gear case, a drum about which said cable iswounda plurality of turns after it leaves said guide sleeve, a tractionpulley around which said cable passes after leaving said drum, said drumand said'traction pulley being secured to the extending end of saidshaft, a lever having one end thereof'pivotally secured to said stirrup,a pressure wheel carried by said lever in alignment with said tractionpulley, an idler pulley carried by said lever in offset relation to saidpressure wheel, said idler pulley being operative to guide said cableonto said traction pulley after it leaves said drum, said pressure wheelbeing operative to hold said cable tight against said traction pulley,and said traction pulley being operative to withdraw said cable from oneend of said drum at the same linear speed that said cable is be ingwound onto the other end of said drum.

2. A swing stage scaffold as defined in claim 1 in which said stirrupcomprises a horizontally disposed bar adapted to support one end of aplank, and two upwardly extending side rods the upper ends of which arepermanently secured to said guide sleeve. I

3. A swing stagescaifold as defined in claim 1 in which said guidesleeve is vertically slotted for the reception of said cable and hasconnected therewith detachable means operative to hold said cable insaid slot.

4. A swing stage scaffold as defined in claim 1. in which said guidesleeve is vertically slotted for the reception of said cable and has asafety brake connected therewith which is operative to hold said cablein said slot and to prevent falling of said stirrup.

5. A swing stage scaffold as defined in claim 4 in which said safetybrake comprises an eccentrically mounted disc which extends into saidslot into engagement with said cable.

6. A swing stage scaffold as defined in claim 1 in which said powermeans comprises a worm gear secured to said shaft within said gear case.

' a worm rotatably mounted in said case in mesh with said worm gear, andan electric motor detachably connected to said worm.

'7. A swing stage scaffold comprising a suspended cable, a stirrupadapted to support a plank, a guide sleeve through which said cablepasses secured to said stirrup adjacent the upper end thereof, a gearcase mounted upon said stirrup in spaced relation to said guide sleeve,a shaft rotatably mounted in said gear case with one end thereofextending out from said gear case, power means by which said shaft isrotated carried by said gear case, a drum about which said cable iswound a plurality of turns after it leaves said guide sleeve, a tractionpulley around which said cable passes after it leaves said drum, saiddrum and said traction pulley being rigidly secured to the extending endof said shaft, a shiftable member movably mounted upon said stirrup, apressure wheel carried by said shiftable member in alignment with saidtraction pulley, an idler pulley carried by said shiftable member inoffset relation to said pressure wheel, said idler pulley beingoperative to guide said cable onto said traction pulley after it leavessaid drum, said pressure wheel being operative to hold said cable tightagainst said traction pulley, and said traction pulley being operativeto withdraw said cable from one end of said drum at the same linearspeed that said cable is being wound onto the other end of said drum.

8. A swing stage scaffold as defined in claim 7 in which said stirrupcomprises a horizontally disposed bar adapted to support one end of aplank, and two upwardly extending side rods the upper ends of which arepermanently secured to said guide sleeve.

9. A swing stage scaffold as defined in claim 7 in which said guidesleeve is vertically slotted for the reception of said cable and hasconnected therewith detachable means operative to hold said cable insaid slot.

10. A swing stage scaffold as defined in claim 7 in which said guidesleeve is vertically slotted for the reception of said cable and has asafety brake connected therewith which is operative to hold said cablein said slot and to prevent falling of said stirrup.

11. A swing stage scaffold as defined in claim 10 in which said safetybrake comprises an eccentrically mounted disc which extends into saidslot into engagement with said cable.

12. A swing stage scaffold as defined in claim 7 in which said powermeans comprises a worm gear secured to said shaft within said gear case,a worm rotatably mounted in said case in mesh with said worm gear, andan electric motor detachably connected to said worm.

13. A swing stage scaffold comprising a suspended cable, a stirrupadapted to support a plank, upper and lower guide sleeves through whichsaid cable passes carried by said stirrup in vertically spaced relationto each other, a driven drum around which said cable is wound aplurality of turns, a driven traction pulley around which said cablepasses after leaving said drum, said drum and said traction pulley beingdisposed between said upper and lower guide sleeves, said tractionpulley being operative when rotated in one direction to withdraw saidcable from said drum and when rotated in the opposite direction to feedsaid cable onto said drum, a first brake carried by said upper guidesleeve and operative in braking position to grip said cable and holdsaid stirrup in fixed position on said cable, a second brake carried bysaid lower guide sleeve and operative when in braking position to gripsaid cable and prevent said traction pulley feeding said cable onto saiddrum.

14. A swing stage scaffold as defined in claim 13 in which said secondbrake is also operative when in braking position to grip said cable andhold said stirrup in fixed position on said cable.

15. A swing stage scaffold as defined in claim 14 in which said firstbrake and said second brake are connected together for actuation inunison.

16. A swing stage scaffold as defined in claim 13 in which said firstbrake and said second brake each comprises an eccentricall mounted discpivotal on its respective sleeve extending into a slot in the sleeve andinto engagement with said cable.

17. A swing stage scaffold as defined in claim 13 in which both of saidbrakes are normally biased to braking position.

18. A swing stage scaffold as defined in claim 17 in which said firstbrake and said second brake are connected together for actuation inunison.

19. A swing stage scaffold as defined in claim 18 in which said firstbrake and said second brake each comprises an eccentrically mounted discwhich extends into a slot in the associated sleeve and into engagementwith said cable.

20. A swing stage scaffold as defined in claim 13 in which said firstbrake and said second brake are connected together for actuation inunison.

RALPH ALLENBAUGI-I.

References Cited in the file of this patent FOREIGN PATENTS NumberCountry Date 690,519 France June 23, 1930

